For the purpose of supplying fuel to the combustion chambers of an internal combustion engine, in particular a diesel fuel internal combustion engine, injection systems are used which in recent years have increasingly been implemented in the form of so-called “common rail” systems. In these systems, the injectors—which are disposed in the combustion chambers—are supplied with fuel from a common fuel accumulator, the common rail. The fuel to be injected is held in said fuel accumulator under a pressure of up to 2000 bar.
Injection systems for internal combustion engines usually have different pumps by means of which fuel is conveyed in order to reach the combustion chambers of the internal combustion engine. Such injection systems for internal combustion engines place high demands on the accuracy of the injection pressure required to inject fuel into the combustion chambers of the internal combustion engine.
This is particularly important since the regulations being enacted with regard to permissible levels of harmful emissions from internal combustion engines in motor vehicles are becoming increasingly stringent. This means it is necessary to carry out various measures to reduce harmful emissions. Thus, for example, the formation of soot is heavily dependent on the preparation of the air/fuel mix in the respective cylinder of the internal combustion engine.
With suitable control and regulating units, the injection system may achieve a highly accurate fuel injection pressure in the combustion chambers of the internal combustion engine.
An injection system for an internal combustion engine is known from EP 1 296 060 B1, said injection system having a prefeed pump, with which fuel may be conveyed from a fuel tank to the suction side of a high-pressure pump. A hydraulic high-pressure pump connected downstream from the prefeed pump then conveys fuel into a fuel accumulator, from whence it may then be distributed to injectors hydraulically coupled to the fuel accumulator.